2) Arrange the giardiniera, corn and roasted bell peppers in piles around the cauliflower. Sprinkle the onions, olives and capers over the vegetables.
3) Whisk the oil, vinegar, and black pepper in a medium bowl to blend. Drizzle the vinaigrette over the vegetables and serve.
The salad can be prepared ahead. Cover the salad and refrigerate it overnight. Bring to room temperature before serving.